ffmpeg jotting

• crop detect:

ffplay -i v_rus.mp4 -vf "cropdetect=24:16:0"

cropdetect=limit:round:reset
limit = black threshold (default 24)
round = output resolution must be divisible to this
reset = after how many frames the detection process will start over

ffmpeg -i in.mp4 -vf "crop values" out.mp4

(source1, source2)